docs: def version_to_string(version):
          """Return the string representation of the given :ref:`SVG_VERSION`.
          See :meth:`get_versions` for a way to get
          the list of valid version ids.
  
          """
          c_string = cairo.cairo_svg_version_to_string(version)
          if c_string == ffi.NULL:
              raise ValueError(version)
          return ffi.string(c_string).decode('ascii')